A majority of commercial hitches have used a ball and socket connection in which the ball is vertically mounted on the towing vehicle and the inverted socket on the coupling member of the trailer. Trailers which have light weights are not difficult to attach to the ball since they can be easily lifted manually and guided into engagement with the ball. However, heavier trailers are difficult to manually attach to a stationary towing vehicle, requiring instead that the towing vehicle maneuver the ball under the stationary inverted socket of the coupling member and then having the operator lower the coupling member into engagement with the ball through the use of a screw jack or other similar device. This alignment process is difficult for an individual since he cannot see the ball and coupling member from the driver's seat of the towing vehicle. To aid in the alignment process, there have been several attempts to create a guiding apparatus which may be used.
U.S. Pat. No. 4,844,496 to Webb et al. shows a trailer hitch guide apparatus that has a ramp bounded by a pair of vertical guides. The apparatus can be assembled with respect to a bumper flange in surrounding relationship to a trailer ball for use in docking the hitch socket to the hitch ball. After the docking procedure is completed, the apparatus is said to be slidably removable from the bumper flange. The apparatus, however, only raises the hitch socket to a point below the level of the hitch ball. As a result, the user must still raise and further align the hitch socket with the hitch ball.
U.S. Pat. No. 4,657,275 to Carroll discloses a self-aligning trailer hitch. This hitch includes a ramp member pivotally attached to an extension member that in turn is slidably engaged with the base of the hitch so that the ramp member and extension member may be readily removed once the trailer hitch coupler has been engaged with the ball. In use, the trailer tongue is lifted and guided by the ramp member to a position above the ball. Continued movement causes the trailer tongue to trip a ramp support that allows the ramp to drop and consequently the trailer tongue. A problem with this device is that recoil of the trailer may cause the tongue to miss or improperly drop onto the ball. As the device is forced against the trailer, rearward travel of the trailer necessarily must be restrained as by wheel chocks. However, play in the trailer suspension will allow the trailer to rock back with stored recoil force. Once the ramp collapses, the trailer will rock forward by reason of the stored recoil force. This forward motion of the trailer may cause the tongue to miss or not properly engage the ball as the tongue drops. Also, the device of this patent requires a special base plate which remains with the ball, whereby the device can only be used with ball hitches equipped with this special base plate.